Sequence-specific, RNA-protein interactions overcome electrostatic barriers preventing assembly of satellite tobacco necrosis virus coat protein.
Sequence-specific, RNA-protein interactions overcome electrostatic barriers preventing assembly of satellite tobacco necrosis virus coat protein.
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DOI：
10.1016/j.jmb.2013.01.004
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发表时间：
2013-03-25
影响因子：
5.6
通讯作者：
Stockley, Peter G.
中科院分区：
文献类型：
--
作者：
Ford, Robert J.;Barker, Amy M.;Bakker, Saskia E.;Coutts, Robert H.;Ranson, Neil A.;Phillips, Simon E. V.;Pearson, Arwen R.;Stockley, Peter G.
我们研究了RNA-外壳蛋白（CP）相互作用在卫星烟草坏死病毒（STNV）组装中的作用。病毒基因组RNA仅编码CP，其包含与带正电荷的N-末端延伸连接的β-桶结构域。在该系统的先前晶体结构中，蛋白质的前11个残基是无序的。使用针对CP B3分离的RNA适体序列的变体，我们研究了RNA诱导组装的序列特异性。B3由呈现四环序列ACAA的茎环组成。对于包含该环序列的RNA存在明显的偏好，如通过T = 1衣壳的产量所测量的，其与茎内的序列无关。含B3的病毒样颗粒已结晶，其结构确定为2.3 μ m。还计算了包含RNA密度的低分辨率图。B3的存在导致位于颗粒3重轴处的N-末端螺旋的有序性增加，其延伸大约一圈半以包含残基8-11，包括R8和K9。在组装条件下，在不存在RNA的情况下，STNV CP是单体的并且不自组装。这些事实表明，一个合理的模型组装启动是特定的RNA诱导的稳定化的三聚体壳粒。螺旋延伸的基本性质表明，CP之间的静电排斥防止在没有RNA的情况下组装，并且通过正确放置适当定向的螺旋RNA茎来克服这种障碍。这样的机制将与这里显示的与更长的RNA片段（包括STNV基因组）组装的数据一致。结果进行了讨论，在光的第一阶段的组装涉及压缩的基因组RNA驱动的多个RNA包装信号CP相互作用。卫星病毒装配中的序列特异性。在病毒CP中siRNA诱导的构象变化。RNA结合克服了CP组装的静电屏障。含有多个优选茎环的cDNA更有效地组装。证据支持单链RNA基因组中存在包装信号。
We have examined the roles of RNA–coat protein (CP) interactions in the assembly of satellite tobacco necrosis virus (STNV). The viral genomic RNA encodes only the CP, which comprises a β-barrel domain connected to a positively charged N-terminal extension. In the previous crystal structures of this system, the first 11 residues of the protein are disordered. Using variants of an RNA aptamer sequence isolated against the CP, B3, we have studied the sequence specificity of RNA-induced assembly. B3 consists of a stem–loop presenting the tetra-loop sequence ACAA. There is a clear preference for RNAs encompassing this loop sequence, as measured by the yield of T = 1 capsids, which is indifferent to sequences within the stem. The B3-containing virus-like particle has been crystallised and its structure was determined to 2.3 Å. A lower-resolution map encompassing density for the RNA has also been calculated. The presence of B3 results in increased ordering of the N-terminal helices located at the particle 3-fold axes, which extend by roughly one and a half turns to encompass residues 8–11, including R8 and K9. Under assembly conditions, STNV CP in the absence of RNA is monomeric and does not self-assemble. These facts suggest that a plausible model for assembly initiation is the specific RNA-induced stabilisation of a trimeric capsomere. The basic nature of the helical extension suggests that electrostatic repulsion between CPs prevents assembly in the absence of RNA and that this barrier is overcome by correct placement of appropriately orientated helical RNA stems. Such a mechanism would be consistent with the data shown here for assembly with longer RNA fragments, including an STNV genome. The results are discussed in light of a first stage of assembly involving compaction of the genomic RNA driven by multiple RNA packaging signal–CP interactions. ► Sequence specificity in satellite virus assembly. ► RNA-induced conformational change in a viral CP. ► RNA binding overcomes an electrostatic barrier to CP assembly. ► RNAs containing multiple preferred stem–loops assemble more efficiently. ► Evidence supports the existence of packaging signals in single-stranded RNA genomes.
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影响因子：
3.7
作者：
Harvey JJ;Lewsey MG;Patel K;Westwood J;Heimstädt S;Carr JP;Baulcombe DC
通讯作者：
Baulcombe DC
影响因子：
2.9
作者：
Devkota, Batsal;Petrov, Anton S.;Harvey, Stephen C.
通讯作者：
Harvey, Stephen C.
影响因子：
5.6
作者：
Lane, Stephen W.;Dennis, Caitriona A.;Phillips, Simon E. V.
通讯作者：
Phillips, Simon E. V.
影响因子：
3.7
作者：
BANCROFT, JB;HILLS, GJ;MARKHAM, R
通讯作者：
MARKHAM, R
影响因子：
5.6
作者：
LILJAS, L;UNGE, T;STRANDBERG, B
通讯作者：
STRANDBERG, B